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[TowerTalk] Quad Element Tuning

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Subject: [TowerTalk] Quad Element Tuning
From: (
Date: Sat, 8 Sep 2001 16:43:58 EDT
In a message dated 9/8/01 11:04:10 AM Pacific Daylight Time, 
   >>  Actually my first gain antenna was a 2L triband quad and K7WA
 > > and I spent  a whole Saturday screwing around with the tuning.
 > > That was it for  quads. That  and the fact that I wanted to put a
 > > 40M yagi up too and couldn't do  it with  the quad.
 > > Cheers,     Steve    K7LXC
 > > Tower Tech
 > >
 > Are you saying that you still can't just "cut and play" with 2L Quads?
 > What about W4RNL's website, or others, for a good set of dimensions.
 > Tom  N4KG
 I don't know what Steve meant, I know that even a 2L multiband quad is a
 challenge and final F/B fair when some band is close to each other or
 harmonically related.
     Modeling and tests proved to me that 12m and 10m loops doesn't live 
 together, expecially in 3 or more elements loop antennas and particularly
 when same parasitic type loops are on a single cross arms.
 I had a  5x10/4x15/3x20 multiband delta loop on a single boom that worked
 fine, but 10 meters stopped (refused) to work properly when the 40m loops
 were added, no matter everything was tried to refine 10m loops.
 People often think that's all right with their multiband directional antenna
 because of a low SWR and some F/B exist, but if they could compare with a
 reference antenna, in some cases the disillusions could be many and big.
 Mauri I4JMY
This 12/10M interference is a puzzling concept.  In all the 5 band 2 element 
tune ups I've done in Eznec I've been able to get clean patterns adjusting 
the reflectors on every band.  So has the W6 that had a 2 element 5 band quad 
in QST.  If 12M affects 10M, why doesn't 15M affect 12M, 17M affect 15M and 
20M affect 17M?  Or the reverse?  I find very little RF on the off band 
elements.  I even added 6M which is further way frequency ratio wise.  I'm 
adding 144/455MHz in the rear.

Here's another one I did just to check out a theory I had.  I drove the 
higher off band DE and then the off band lower DE and got great 
patterns--sometime better F/B.  The Z's were way off but fed with open wire 
line and into the proper tuner it will still put max RF into the DE.  I will 
check out the patterns in actual practice.  

Now Exnec hasn't lied to me yet.  Since this produces great patterns without 
any retuning I would then have to assume there is some querk of 12&10M that 
does this that is compensated for by retuning the 12M reflector the right 
amount.  So I have to ask--"were the 12 or 10M elements ever retuned.  If it 
works in Exnec I'm taking bets it works in actual practice.  Are there any 
betters?  k7gco  

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